Note: I have deployed two vCenters named vCenter1 and vCenter2, New Windows machines for external SSO/PSC named PSC1 and PSC2 respectively. This article uses same names for upgrading vCenter 5.5 to vCenter 6.0

Deploy a new VMware vCenter Single Sign-On machine for VMware vCenter Server on PSC1

Deploy a new Microsoft Windows Server on a physical or virtual machine that meets the software and hardware requirements for your version of VMware vCenter Single Sign-On.

Check Build number of vCenter and use same build number ISO to install Single Sign-On.

Hello ,
Good Post , have few questions.
1. You are moving Embedded SSO to External SSO on First go
2.uninstall SSO on second go
3. upgrade SSO as PSC finally
correct me if understanding is wrong.
just curious to know below
1. repoint to external sso does this Migrate embedded SSO DB to external SSO ?
2. why uninstall? why not direc upgrade?
3. even after uninstall why PSC able to see previous sso deployment?
4.what are steps needed if we use Vcenter appliance and windows vcenter in combination from original setup?

2. why uninstall? why not direc upgrade?
— We can do direct upgrade but if we have SSO component also available on same embedded vCenter it will also upgrade SSO. So it would be better if we uninstall SSO to make sure no one confuse.

3. even after uninstall why PSC able to see previous sso deployment?
— PSC only detects if SSO is installed but while upgrading vCenter it requires PSC details. If SSO is uninstalled only vCenter components will be upgraded.

4.what are steps needed if we use Vcenter appliance and windows vcenter in combination from original setup?
— I think vCenter appliance in linked mode is not possible for 5.1/5.5 vSphere.